SDLAM Determination Modelling 28 June 2018 Operation of the - - PowerPoint PPT Presentation

SDLAM Determination Modelling

28 June 2018

Operation of the mechanism

Add package of supply projects Run supply package modelling scenario Basin Plan scenario in the model (2750 GL water recovery) Final adjustment volume Check ecology scores Reduce water recovery Check limits of change Check reliability of supply metrics PPMs must be in place by 30 June 2019

Environmental equivalence

• Supply measures must achieve equivalent or better environmental
• utcomes
• Compares SDLAM package to benchmark modelling runs
• Scoring method was developed by CSIRO to compare environmental
• utcomes = ‘ecological elements’
• Overall score must be equal or better
• Trade-off allowed between elements and reaches
• Limits of change (constrain the trade-off)
• The determination also cannot have detrimental impacts on reliability

The components of the framework used to determine the SDL adjustments are:

Modelling

• MDBA has a modelling framework

representing rivers in the Murray– Darling Basin

• It includes dams, weirs, water

supply for towns, irrigators and agriculture, etc

• Modelling period: 114 years

historical record (1895 – 2009)

Hydrology Modelling Framework

Time Flow

Benchmark Scenario 2,750 GL — fully implemented Basin Plan 2012

Without Basin Plan With Basin Plan

Translate flow into Environmental Outcomes Baseflows Freshes Bankfull Overbank Coorong Lower Lakes Murray Mouth Ecological Elements (environmental score)

Limits of Change

Assessing environmental water needs

Ecological elements

Twelve biological elements of the ecosystem, the ‘ecological elements’ are used by the framework to capture flow-related environmental outcomes.

Ecological elements – spatial

Preference curves – benthic herb lands

Value Value

1 2 3 4 5 6 7 9 8 3 2 1 0.2 0.4 0.6 0.8 1 0.2 0.4 0.6 0.8 1

Years since SFI last met Consecutive years SFIs met

Good Critical Medium Poor

Score Ave = 0.68

Example – short lived fish

Federation drought, ‘bad’ for short lived fish, low score Wet 1950s and 1970s – ‘good’, high score Millennium drought– bad for short lived fish, low score

Types of limits of change

Baseflow and freshes

• Relate to SFIs
• Requires no reduction in outcomes achieved in the benchmark run

Bankfull and overbank

• Relate to SFIs
• Seven different rules can be applied to determine LoC

Coorong, Lower Lakes and Murray Mouth

• Five outcomes are required
• Relate to salinity, barrage flows and mouth openness

Reach 1 Reach 2

Class Ecological Element EE Score EE Score Reach Score Bird Waterbirds (health) 6786 5348 7002 Bitterns, crakes & rails 5526 Colonial nesting waterbirds 4395 Waterbirds (breeding) 4684 Vegetation River Red Gum forests 7896 7571 River Red Gum woodlands 8086 Blackbox forests and woodlands 8719 Shrublands na Tall grasses, sedge & rushlands 6425 Benthic herblands 7270 Fish Short-lived fish 8117 8086 Long-lived fish 8055

Benchmark Scenario – Ecological Elements – Reach 1

Class Ecological Element EE Score EE Score Reach Score …. …. …. …. 6200

Benchmark Scenario – Ecological Elements – Reach 2

A Simple Example Application

Reach 1 Reach 2

Benchmark Scenario Results

EE Scores Reach 1: 7002 Reach 2: 6200 Combined: 6846 Baseflow Reach 1: 93% Reach 2: 82% SFIs (freshes, bankfull,

• verbank)

SFI 1 (lower FP): 72% SFI 2 (upper FP): 63% SFI 3: …… Coorong (EOS) Salinity, flow, openness

Limits of Change

EE Scores Combined: no decrease (trade-off allowed between reaches) Baseflow Reach 1: no decrease Reach 2: no decrease SFIs (freshes, bankfull,

• verbank)

SFI 1 (lower FP): 68% SFI 2 (upper FP): 61% SFI 3: …… Coorong (EOS) Salinity, flow, openness

A Simple Example Application

Reach 1 Reach 2 Supply measure 1 Environmental works Supply measure 2 Constraints, EWM & operations

Benchmark Scenario Results

EE Scores Reach 1: 7002 Reach 2: 6200 Combined: 6846 Baseflow Reach 1: 93% Reach 2: 82% SFIs (freshes, bankfull,

• verbank)

SFI 1 (lower FP): 72% SFI 2 (upper FP): 63% SFI 3: …… Coorong (EOS) Salinity, flow, openness

Limits of Change

EE Scores Combined: no decrease (trade-off allowed between reaches) Baseflow Reach 1: no decrease Reach 2: no decrease SFIs (freshes, bankfull,

• verbank)

SFI 1 (lower FP): 68% SFI 2 (upper FP): 61% SFI 3: …… Coorong (EOS) Salinity, flow, openness

A Simple Example Application

Reach 1 Reach 2 Supply measure 1 Environmental works Supply measure 2 Constraints, EWM & operations

Benchmark Scenario Results

EE Scores Reach 1: 7002 Reach 2: 6200 Combined: 6846 Baseflow Reach 1: 93% Reach 2: 82% SFIs (freshes, bankfull,

• verbank)

SFI 1 (lower FP): 72% SFI 2 (upper FP): 63% SFI 3: …… Coorong (EOS) Salinity, flow, openness

Supply Measure Scenario Results

EE Scores Reach 1: 7246 Reach 2: 6047 Combined: 6846 Baseflow Reach 1: 93% Reach 2: 82% SFIs (freshes, bankfull,

• verbank)

SFI 1 (lower FP): 69% SFI 2 (upper FP): 65% SFI 3: …… Coorong (EOS) Salinity, flow, openness

A Simple Example Application

SDL adjustment proposals

5

• 2013 – Benchmark model, ecological elements

development

• 2014/15 – Trial of the model/EE framework with 6

measures – wide exposure of the SDLAM method

• 2015/16 – Progress towards 19 measures
• Late 2016 – States advised to propose more

projects to bring new water into the system

→ Menindee Lakes, HydroCues (EEWD), Constraints

• 2017 – Finalisation of determination – 605 GL

SDL adjustment timeline

Brooks et al. Independent Reviews Bewsher Expert Panel Bewsher

Scores for:

Fish (2) Vegetation (6) Waterbirds (4) Reach scores

Each flow indicator score is weighted by the proportional area within the reach of that element and combined to give a EE score for the reach. Each EE score is averaged to get a reach EC score

Regional score

Ecological Elements scoring method

Compare Basin Plan benchmark to Increased SDL with supply measures

}

Increase SDL until achieve environmental equivalence within agreed safeguards

Menindee Lakes

Purchase of major high security entitlements Pipeline to supply Broken Hill New outlet – Lake Menindee Regulator separates Lakes Menindee and Cawndilla Lake Cawndilla – largely dry Constraint management 14 000 ML/day Weir 32

• Evaporative savings
• Higher release rates
• Less dead storage

Lake Menindee Lake Cawndilla Lake Pamamaroo

Copi Hollow

Darling River

Weir 32 Menindee Outlet Regulator Pamamaroo Outlet Regulator Main Weir Menindee Inlet Regulator

To Lake Tandou and Darling Anabranch

Cawndilla Outlet Regulator

Menindee

Enhanced Environmental Water Delivery

Hydro cues = a water delivery strategy

June November Lower floodplain In channel July August September October Regulated flow boundary (constraint)

River

• perators

Targeted trigger Flow trigger

Address physical and policy constraints to allow higher regulated flows.

• Hume to Yarrawonga key focus area (40 000 ML/d)
• Yarrawonga to Wakool junction key focus area (50 000 ML/d)
• South Australian Murray key focus area (80 000 ML/d)
• Murrumbidgee key focus area (40 000 ML/d)
• Goulburn – not a supply project - (stage 1 - 20 000 ML/d)

Constraints relaxation

Assessment Reach Without Development Baseline Benchmark SDL 605 Upper-Murray – Barmah-Millewa Forest 6935 4003 5100 5017 Upper-central Murray – Gunbower- Koondrook-Perricoota 7030 3405 5567 6376 Mid-Murray – Hattah Lakes 5577 2738 3387 3955 Lower-Murray - Chowilla 6080 2791 3970 4271 Edward Wakool 6292 3224 4169 4120 Lower Darling 4271 2637 2791 2805 Mid- Murrumbidgee 6360 4163 4646 4495 Lower Murrumbidgee 7524 5094 6502 6331 Lower Goulburn Floodplain 8641 6814 8219 8038 Southern basin region score 6523 3874 4928 5045

Ecological Elements Reach Scores

KEY TO SYMBOLS

Lake Victoria Hattah Lakes Coorong, Lower Lakes and Murray Mouth Riverland-Chowilla Floodplain Edward-Wakool River System Gunbower- Koondrook- Perricoota Forest Barmah-Millewa Forest Lower Murrumbidgee Floodplain Mid-Murrumbidgee Wetlands Lower Darling Floodplain

Site-specific flow indicators’ performance against the limits of change

Lower Goulburn Floodplain

SFI breaching LoC SFI within 1% of LoC SFI >5% away from LoC SFI >1%,<5% away from LoC

Murrumbidgee freshes

Why is the Lower Darling limit of change not being achieved?

• Key proposed changes to Menindee Lakes:
• New infrastructure
• Regulator between Menindee and Cawndilla
• Weir 32 expansion
• Inlet and regulator between the Lower Darling and Darling Anabranch
• Higher managed flows
• Increased flow rate at Weir 32
• Fill and spill pattern changes
• Menindee and Cawndilla
• Weir 32
• More flows in the Darling Anabranch

Model scenarios comparison at Weir 32

Model scenarios comparison at Wycot

Office locations Adelaide Albury-Wodonga Canberra Toowoomba mdba.gov.au 1800 630 114 engagement@mdba.gov.au Office locations Adelaide Albury-Wodonga Canberra Toowoomba mdba.gov.au 1800 630 114 engagement@mdba.gov.au

Thank you.